We started off with the Bentley Bentayga W12, an unapologetic behemoth with a 608hp 6.0-litre petrol engine. Then Bentley seemed to develop an eco-conscience and gave us the Bentayga Diesel, using the underpinnings from the wonderful Audi SQ7. And then there was a downsized petrol model, with, er, a 4.0-litre, 550hp twin-turbo V8. But as all of these Bentaygas are leather-lined luxury palaces on wheels, in terms of their size and weight, then the quoted economy and emissions numbers have never made the most pleasant of reading. Well, all that's about to change.

How so?

At the Geneva Motor Show, Bentley has pulled the covers off the Bentayga Hybrid. Now, it's actually a plug-in hybrid electric vehicle (PHEV), but Bentley has clearly decided it doesn't like the term PHEV and so Hybrid it is. However, the distinction is important to make, because a) it allows Bentley to claim this is the 'world's first luxury hybrid model' (although we're sure that, at the very least, Land Rover would have something to say about that assertion ...), and b) it means the Bentayga Hybrid has some impressive green stats. Like an all-electric, zero-emissions range of 31 miles on a full charge, or just 75g/km of CO2 emissions. That latter number compares extremely favourably to the Diesel (210g/km), V8 (260g/km) and W12 (296g/km) Bentaygas, we can tell you.

Impressive stuff, certainly for company car tax implications. So what about the powertrain?

Ah. Bentley is being a touch coy here. We know there's a 3.0-litre turbocharged V6 petrol as the main form of power, augmented by an E Motor and a battery pack that can take a full charge in just 7.5 hours on a domestic socket, or 2.5 hours if you've got some DC power in your life. We know order books won't open until the second half of this year, in selected markets only, meaning the Bentayga Hybrid won't hit the streets until some point in 2019.

And we know the Bentley PHEV should have all the attributes of your regular Bentaygas - hand-made wood and leather-clad cabins replete with a massive array of opulent gizmos, ride and handling characteristics befitting of this British upmarket company, the ability to personalise details to the nth degree and so on. There's even a home charging unit, made of sustainable materials, which is designed by Philippe Starck (that's the fella in the pictures). It's called the 'Timeless Bentley by Starck Power Dock'. No, really.

Hmm. Anyway, can I easily identify the Bentayga Hybrid, just by looking at it?

Yes, as the 'Hybrid' badges on the lower portions of the front doors and on the tailgate, plus the Bentley logos and alloy wheel centres are all finished in copper. There's also a plug-in charging port on the nearside-rear of the big SUV and, inside, new gauges and read-outs keep the driver fully informed as to the status, workload and charge level of the hybrid running gear.

Any statements from the Bentley team?

Adrian Hallmark, the newly appointed chairman and CEO of Bentley Motors, said: "The Bentayga Hybrid is our first step on the road to electrification, combining traditional Bentley values with the very latest technologies. It gives customers the best of both worlds - engaging, effortless performance on the open road and silent, emission-free driving in the city, which will become increasingly important with the ever-changing regulations around the world. Following Bentley tradition, the Bentayga Hybrid pioneers a new automotive sector - the luxury hybrid - and sets Bentley on the path towards a sustainable electrified future."